Olympics Arms are one of the only ones that are made in house. Pretty much all the other companys buy there parts from vendors. You can't go wrong with any of the big names. I myself have a CMMG lower, RRA lower parts with a NM 2-stage trigger, and a Bushmaster Varminter upper. It shoots 1/2" with UltraMax ammo, I can't wait until I start to tune a load for it.